San Jose Earthquakes clinched the final play-off spot in dramatic fashion on the last day of the MLS regular season.
Marco Urena struck in the third minute of stoppage time to secure his side a 3-2 win against Minnesota United and their first play-off place since 2012.
San Jose twice led through Danny Hoesen and Chris Wondolowski, but Jerome Thiesson and then Francisco Calvo replied for Minnesota.
Dallas' season is therefore over despite thrashing 10-man Los Angeles Galaxy 5-1.
San Jose's win also ended Real Salt Lake's hopes of extending their season and they signed off with a 2-0 win against Sporting Kansas City.
Elsewhere in the Western Conference, Portland Timbers beat Vancouver Whitecaps 2-1 in a battle for the number one seed.
Kendall Waston gave the Whitecaps the lead, but goals from Liam Ridgewell and Darren Mattocks turned the game around.
Vancouver's defeat proved costly as they miss out on a first-round bye, with Seattle Sounders pipping them to the second seed.
The Sounders survived the sending-off of Clint Dempsey and conceding a penalty to beat Colorado Rapids 3-0, with Nicolas Lodeiro scoring twice after Axel Sjoberg's red card levelled the playing field.
Will Bruin tapped in the opener before Dempsey was shown a straight red for an elbow in the 24th minute, while Colorado's Dominque Badji hit the left post from the spot with the score 1-0.
Vancouver will host San Jose in the Western play-offs, with Sporting travelling to Houston Dynamo.
The Eastern Conference play-off teams were already known, but New York City clinched the second seed to earn a bye.
David Villa scored twice as Patrick Vieira's side drew 2-2 with Columbus Crew.
That left the door open for Chicago Fire and Atlanta United, but neither could take advantage.
Chicago lost 3-0 to Houston while Atlanta were pegged back twice by number one seed Toronto in a 2-2 draw and will now host Columbus next week.
New York Red Bulls, who will be Chicago's play-off opponents, warmed up by coming from behind to beat DC United 2-1.
Elsewhere, the Philadelphia Union ended their campaign with a 6-1 thrashing of Orlando City, while Matteo Mancosu's 90th-minute equaliser counted for nothing as Kelyn Rowe struck six minutes into stoppage time to earn the New England Revolution a 3-2 win against Montreal Impact.